Orthopaedic fixation systems serve to fix bones or bone fragments relative to one another. For example, the fixation system can be used in the area of spinal fixation, wherein anchoring elements in the form of bone screws are anchored on the vertebrae to be stabilised relative to one another. These are connected to one another by means of the stabilisation element in the form of a rod, which runs along the spinal cord and is secured by clamping into the stabilisation element seatings of the bone screws, i.e. the screw heads, for example.
Irrespective of where the fixation is used on the body, it is desirable to work in a minimally invasive manner. For example, percutaneous fixation methods have been developed, in which both the anchoring elements and the stabilisation element can be inserted into the body through only relatively small incisions. However, this makes alignment of the stabilisation element relative to the stabilisation element seating difficult, in particular when more than only two anchoring elements are to be connected to one another.
In order to align the stabilisation element correctly relative to an anchoring element to insert it into the stabilisation element seating in an insertion direction, it is known to predefine a corresponding guide path for the stabilisation element. For example, in the case of fixation systems and fixation methods according to U.S. Pat. No. 7,455,685 B2 and DE 100 27 988 A1 extension devices are in each case detachably connected to the anchoring elements at a distal end. The respective proximal ends, i.e. the ends facing the operating surgeon, of the extension devices project out of the body and the stabilisation element is held on them to pivot along a circular arc. These fixation systems have the disadvantage that they are mechanically complex and the stabilisation element can only be guided through the anchoring elements along a circular arc.
Fixation systems and fixation methods are known from WO2007/146833 A2 and from U.S. Pat. No. 7,473,267 B2, in which extension devices are also detachably connected to the anchoring elements, and in which a guide element, e.g. a thin wire, is firstly threaded through the stabilisation element seatings before insertion of the stabilisation element. This likewise requires a high equipment expenditure as well as an additional work step.
There is a need to provide an orthopaedic fixation system and method that enable easier alignment of the anchoring element and the stabilisation element relative to one another and thus easier insertion of the stabilisation element into the stabilisation element seating.